Fragment Upload Size for Cloud Storage (S3)

When syncing to an S3-based cloud storage service, Mylio Photos uploads large files in smaller pieces called fragments. The Fragment Upload Size setting controls how large each of those pieces is.

This article explains what fragment upload size is, why it exists, when you might adjust it, and when you should leave it alone.

What Is Fragment Upload Size?

Instead of uploading a large file (such as a multi-gigabyte video) all at once, Mylio Photos splits it into smaller fragments and uploads them one at a time.

For example:

• A 2 GB video may be uploaded as many smaller fragments instead of one large file.

• If an upload is interrupted, only the failed fragment needs to retry instead of restarting the entire file.

Fragment Upload Size determines how big each fragment is.

This setting applies only to S3-compatible cloud storage devices, such as:

• Backblaze B2

• Wasabi

• Amazon S3–compatible storage

• NAS devices configured as an S3 private cloud (for example, using MinIO)

It does not apply to Mylio Drive+ with SecureCloud storage, local drives or non-S3 cloud services.

Why This Setting Exists

Using fragments improves reliability, but there is a tradeoff:

Smaller fragments

• More reliable on unstable connections

• Create more upload overhead

• Can result in thousands of upload parts for very large files

Larger fragments

• Reduce the number of upload parts

• Improve performance on fast, stable connections

• May be less reliable on slow or unstable networks

Some S3 implementations also limit how many fragments a single file can be split into. If that limit is reached, large uploads may fail unless the fragment size is increased.

Default Setting (Recommended)

The default Fragment Upload Size is chosen to work well for most users and most internet connections. In most cases, you should not change this setting. If uploads are working normally, leave the default value unchanged.

When You Might Want to Increase Fragment Upload Size

Increasing the fragment size reduces the total number of fragments created.

This can help if:

• Very large files (such as long videos) fail to upload

• Uploads fail partway through with an S3-based service

• You are using a fast, stable connection (wired Ethernet, local NAS, fiber internet)

This is most commonly useful when syncing to:

• NAS devices configured as S3 private clouds

• High-bandwidth, low-latency networks

When You Might Want to Decrease Fragment Upload Size

Decreasing the fragment size increases reliability on unstable connections.

You might lower the fragment size if:

• Your internet connection is slow or unreliable

• Uploads frequently pause or fail

• You are syncing over Wi-Fi or a mobile hotspot

Smaller fragments reduce how much data must be reuploaded after a failure, but they increase overhead and total upload time.

Important Notes and Limitations

• This is an advanced setting intended for troubleshooting or specialized setups.

• Very large fragment sizes may not perform well on slower connections.

• Very small fragment sizes may slow uploads or hit fragment-count limits on some S3 services.

• Changes to Fragment Upload Size affect new uploads only. Existing uploaded files are not modified.

• This setting applies only to S3-compatible cloud devices.

If you are unsure, leave the setting at its default value.

Summary

• Fragment Upload Size controls how cloud uploads are split into smaller pieces

• The default setting works well for most users

• Increase it for large files on fast, stable connections

• Decrease it for slower or less reliable connections

• Applies only to S3-based cloud storage

This setting should only be adjusted when troubleshooting upload behavior or working with very large files.